The first Red Flag Warnings of the fall remained up Sunday, as a mild Santa Ana Wind condition heated the Los Angeles basin up a bit.
But a drastic change was possible over the next two days, as thunderstorms and spotty rain were likely to sweep up from Mexico, the National Weather Service said.
Inland mountains in Los Angeles and Ventura counties were covered by the warning, as winds picked up from the desert and the air dried and heated as it was pushed out towards the sea.
But it was a relatively weak Santa Ana — peak gusts up to 30 miles per hour were the top predicted speeds.
The air was toasting up to 00000 degrees and baking out to around 5-10 percent relative humidity, according to the National Weather Service.
“The very warm and dry air mass will persist through Monday morning,” said the Red Flag Warning issued by the NWS in Oxnard.
But muggy and hot weather was promised for Monday evening and Tuesday, as subtropical moisture from the south was poised to pulse northward.
The percentage of moisture in the air was to increase by Monday afternoon, particularly in eastern Los Angeles and Orange counties and the Inland Empire. And a low pressure system arriving form the northwest could trigger thunderstorms.
“The initial surge of mid-level moisture and instability will bring the greatest threat of isolated dry lightning strikes on Monday afternoon and evening,” the NWS advisory stated.
“This dry lightning threat would bring the increased threat for new fire ignitions due to the preceding hot and dry conditions, and extremely dry fuels.”
If there are any thunderstorms Tuesday, they will be wetter than Monday’s dry lightning clouds, the NWS said.
Red Flag Warnings were up for the Los Angeles and Ventura counties interior mountains through noon Monday.
The rest of the region, including the Santa Monica Mountains, were under a Fire Weather Watch through Monday evening.
–City News Service